Why cant we submit Engine recordings for Harmonic Analysis--I am very Frustrated and I've been searching he Posts for all the posts on funny engine noise and it dawned on me that all though many of us are good writers, "rattle-rattle"/"thump/thump" "woof woof" just doesnt cut it..why cant we all agree to use a certain Microphone palced at a certain point or ditance from the car using the same software on our PCs and submit our engine recordings on AVI files and getr some software to break them down into different categories of problems...

The reason:
I ask this 20 year Foreign car mechanic a lot of questions and recently I asked him to listen to my 300D W123 which lost oil and ran itself down to 0 bars.
He said the engine is dead and tired and to get rid of it. But you know what--he's been wrong before, and sometimes I wonder if he wants me to buy a new engine from him..(boy i am getting aparanoid in my middle age)

I just dont believe him. I hear a Rattling/Missing sound that drives me crazy and which makes the car sound like one of those 60's Gasser Hotrods that arent running right I used to here in the high school parking lot...

He says its bearings, crank bearings/ connecting rod bearings...

I just dont believe him. The car does a 100 mph and doesnt lose a drop of oil and has plenty of power, but the Rattling/missing sound just drives me crazy...

I know its not a bd injector because I replaced them all.

I am noot Loathe to pull the engine and rebuild it, I just dont want to do it for the wrong reason...

1. Locate another reliable independant "Wrench Turner" (some
-one on this forum should be able to help with that)
2. No oil burn , acceptable top end speed : can be decieving
;remember that engine is almost indestructable up to the
very instant it refuses to start due to lack of compression.
3. Have "Indie" perform compression , "Blowby" , and
leakdown tests.
4. What's the Oil Pressure ??? (Bad Bearings kill your O.P.
[sometimes] )

Compression/blowby/oil pressure are fine

The diagnosis of your mechanic sounds reasonable to me. If you really did run the car with no oil pressure I'm sure the main/rod are now a bit messed up. If the bearing are a bit messed up the car would run just fine, right up to the point were it did not run at all.

I think if it was possible to diagnose an engine by audio analysis somebody smarter than us would have figured out how to do it by now.

here in New Jersey with 87% humidity. You are probably right but changing out an engine is a whale of a job in this heat and after that possibly rebuilding it....